Cyclic shifts applicable for root sequence to generate 1st preamble transmittion (msg1)

Cell range C2.

Ok, means you are using short preamble, not long preamble.

What is SCS for C2?

Yes, short RACH used for NR A2, B2, C2.

it’s 30 kHz.

What is your average inter site distance for NR carrier?
I am asking because do you really need cell radius of 4.6 km?

Outer site with TA 900 meter.

Don’t have planning input, but yes I think site capturing high TA samples.

I would suggest to try changing from 0 to 14 or 15 , in order to improve RACH SR.
Try 1st with 15.